Sensor device

ABSTRACT

The invention relates to a sensor device with a beaker-like sensor housing and a wired sensor, wherein the beaker-like sensor housing has an introduction region for the wired sensor. Furthermore, an orientation region for the sensor and a placement region of the sensor close to the end face of the sensor housing is provided. According to the invention, the orientation region has an internal cross-sectional contour which is adapted to the cross-sectional contour of the sensor, and the sensor is introduced into a curable material in its placement region in the sensor housing.

This application claims the benefit and priority of German Utility Model No. 20 2019 004 415.9, filed Oct. 28, 2019. The entire disclosure of the above application is incorporated herein by reference.

The invention relates to a sensor device with a beaker-like sensor housing and a wired sensor, wherein the beaker-like sensor housing has an introduction region for the wired sensor and also an orientation region for the sensor and a placement region of the sensor close to the end face of the sensor housing.

Sensor devices of this type are used above all on wheels or bikes in order to detect the distances covered, speeds and further parameters of the bike, for example by way of magnetic pulses.

With the known sensor devices, above all problems of precise arrangement on the frame of the bikes but also inaccuracies in the measurement detection occur, which originate from the sensor and its sensor housing, since they are not designed sufficiently robustly for various cycling purposes.

In particular, an inaccuracy in the measurement data may result from the actual sensor not being arranged reliably securely and precisely in the sensor housing, and, owing to the action of impact forces, undergoing changes in position which ultimately lead to measuring inaccuracies.

The sensor device itself should also be able to be arranged simply and precisely on the frame of bikes.

Taking these disadvantages into account, the object is therefore to design a sensor device of the generic type such that the measuring accuracy of the sensor device is maintained even in the case of externally acting forces such as vibrations or impact forces.

This object is achieved by the features of the characterising clause of Claim 1.

One essential core concept in such case is to be able very accurately to introduce the wired sensor into the sensor housing and arrange it therein, with the arrangement of the sensor in the sensor housing being maintained even in the event of different applications of force. This ensures that the measuring accuracy of the sensor device too is not impaired even in the event of sudden applications of force.

On one hand, the design that the sensor upon introduction into the beaker-like sensor housing has to be guided through an internal cross-sectional contour of the orientation region and the sensor itself has a corresponding cross-sectional contour which is adapted to the internal cross-sectional contour of the orientation region contributes to the high measuring accuracy. The corresponding orientation of the sensor upon introduction up to the placement region close to the inside of the end face of the sensor housing and the embedding in the cured material therefore yield a fixed position of the sensor in the sensor housing.

The introduction of the sensor into the sensor housing takes place in such case into a curable material introduced in the interior of the sensor housing, in particular a free-flowing plastics material or resin, with the curable material being cured by temperature or by radiation once the sensor has been placed in the region of the inner face of the end face of the sensor housing.

In the introduction region of the sensor housing, elongate guide bars are provided, preferably distributed over the inner periphery of the sensor housing, by means of which guide bars the sensor can be introduced axially and centrally into the orientation region of the sensor housing, in order there, because of the adapted contours, to achieve its orientation which is necessary for the high measuring accuracy, for example in a particular angular arrangement.

In particular, four guide bars provided at the same angular distance from each other are provided in the introduction region for this.

Upon introducing the sensor which is connected to a cable into the inner region of the sensor housing, a tapering cross-section is provided after the introduction region on the orientation region or in front of the orientation region, so that the sensor can be inserted even more simply and accurately into the orientation region, which may in particular have a cross-section in the form of an oval.

After this orientation operation, the sensor with the cable is guided on through the free-flowing, curable material into its proper placement region close to the inside of the end face of the sensor housing.

This manufacturing operation expediently takes place with a vertical arrangement of the beaker-like sensor housing with an upward-pointing opening and at the bottom an end face which is closed in the base region.

One improvement is achieved in the case of the sensor device in that a strain relief means is arranged on the cable which is connected to the sensor. This may be done in a simple manner by arranging an O-ring on the cable. In such case, it is preferred for the opening of the O-ring to produce a press fit on the cable sheath, in order to absorb forces acting on the cable from the outside and to transmit them to the entire sensor housing. The O-ring is therefore preferably fixed in a ring groove on the introduction region of the sensor housing. Expediently, the fixing of the O-ring takes place after the curing of the material introduced in the interior of the sensor housing.

The possibility of strain relief by an O-ring fixed to the sensor housing also has the advantage that this different strain relief can also be realised with different openings of O-rings.

The closure by means of an O-ring also aesthetically covers over the filled and cured material.

The sensor housing is preferably produced from a plastics material. In particular the plastics material having the brand name “Lexan” is suitable for this purpose. Expediently, a Reed contact is used as sensor or sensor element, which contact can be closed or opened by the influence of magnetic fields. With regard to good detectability of a magnetic field which occurs in the vicinity of the outer end face of the beaker-like sensor housing, the sensor is placed very close to the inner end-face region of the sensor housing.

The free-flowing plastics material or resin which has been introduced in an air-free and bubble-free manner into the interior of the sensor housing therefore, once the material has been cured, ensures that an accurate arrangement of the sensor in the sensor housing is maintained.

A somewhat altered production method may also take into account that the wired sensor is introduced and placed into the beaker-like sensor housing prior to the introduction of the free-flowing material, and only subsequently is the free-flowing embedding material introduced into the interior of the beaker-like sensor housing.

The invention will be discussed in greater detail below with reference to two schematic drawings, in which:

FIG. 1 is a longitudinal section through a sensor housing, without the sensor and cable but with strain relief provided on the end; and

FIG. 2 somewhat enlarged, is a vertical section through a sensor housing as illustrated in FIG. 1 without strain relief on the end, viewed from the left; the schematic section according to FIG. 1 is marked A-A in FIG. 2.

The sensor device according to the invention is shown schematically and discussed in greater detail below with reference to two schematic representations of the essential module, namely a sensor housing 1, without the actual sensor or the sensor element and without a corresponding cable connection.

The longitudinal section of FIG. 1 through a beaker-like sensor housing 1 shows the beaker of the sensor housing 1 which is produced in particular in one piece from a plastics material, such as Lexan. The left-hand end region of the sensor housing 1 shows an opening, into which an O-ring 21 is inserted and fixed.

The sensor housing 1 is closed in the manner of a beaker on the end face 7 on the right.

In the production operation for the sensor device, the sensor housing 1 is usually arranged with its left-hand-side opening upwards in a vertical position.

Then a curable, free-flowing material or a resin is introduced into the beaker 6 of the sensor housing 1. Subsequently, the actual sensor with its connected cable is inserted into the upper opening of the beaker 6 and is guided or lowered centrally from the introduction region 3 into the orientation region 4 by means of the guide rails 11. The sensor is oriented by means of the internal contour, which is configured as an oval 16, by way of the conical tapered region 14.

The sensor or the sensor element in the example illustrated likewise has the external form of the corresponding oval 16, so that the sensor can be guided with an exact fit into the right-hand or lower placement region 5 through the oval 16.

Once the end position of the sensor in the region of the inner face of the end face 7 has been reached, subsequently the curing operation of the curable material is carried out, it being possible to realise air-free and bubble-free embedding and fixing of the sensor in the sensor housing 1.

The O-ring 21 which is attached to the cable for strain relief of the sensor can be fixed in a ring groove on the opening side of the introduction region 3 once the free-flowing material has been cured and possibly also prior to curing. Thus a closure is thereby provided also with respect to the embedding and encapsulation material.

In this design, the sensor device represents a very accurately arranged sensor, which is not adversely affected in its relative positioning in the interior of the sensor housing even by acting impact forces, and thus also ensures high measuring accuracy.

An annular bead 25 in the middle region of the sensor housing 1 may also serve for accurate positioning of the sensor housing 1 on the frame of a bike, with clamping holders performing the further fastening to the frame of a bike on one side or on both sides of the annular bead 25. 

1. A sensor device with a beaker-like sensor housing and a wired sensor, wherein the beaker-like sensor housing has an introduction region for the wired sensor, an orientation region for the sensor, and a placement region of the sensor close to the end face of the sensor housing, wherein the orientation region has an internal cross-sectional contour which is adapted to the cross-sectional contour of the sensor, the sensor in the sensor housing is introduced into a curable material into its placement region, and the curable material is cured with the sensor embedded.
 2. The sensor device according to claim 1, wherein a strain relief means for the cable and sensor, in particular formed as an O-ring, with a cable-adapted opening, is provided on the introduction region of the sensor housing.
 3. The sensor device according to claim 1, wherein guide bars for the sensor, in particular four guide bars at the same angular distance from each other, are provided in the introduction region.
 4. The sensor device according to claim 1, wherein a tapering cross-section for guiding the sensor into the placement region is provided in front of or on the orientation region of the sensor.
 5. The sensor device according to claim 1, wherein the sensor is introduced into the curable material.
 6. The sensor device according to claim 1, wherein the curable material is a free-flowing plastics material or a resin.
 7. The sensor device according to claim 1, wherein the sensor housing is produced from a plastics material, in particular Lexan.
 8. The sensor device according to claim 1, wherein the orientation region has a cross-section in the form of an oval.
 9. The sensor device according to claim 1, wherein the beaker-like sensor housing has an end-face closure, in the vicinity of which the detection zone of the sensor, which is formed in particular as a Reed contact, is provided.
 10. The sensor device according to claim 1, wherein the curable material is introduced and cured once the sensor has been introduced into its placement region. 